Question

I am creating an interface say ‘Car’

public interface Car {
    public void drive(int Speed, int Gear ); // for cars which have gears
    public void drive(int Speed); // for cars which do not have gears
}

Now i am creating my implimentation classes say SimpleCar and AdvanceCar where

• SimpleCar do not have gears
• AdvanceCar have gears

Now when i write my implementation classes i am forced to code for both the methods even though i do not want them in my implementation classes

public class SimpleCar implements Car {
    public void drive(int Speed, int Gear ){ ... }; // dont want this method in SimpleCar
    public void drive(int Speed ){ ... };
}

can someone help me design my interface which has a method but the implementation classes have different signatures?

Answer 1

public interface Car {

    public void drive(int Speed, int Gear); // for cars which have gears

    public void drive(int Speed); // for cars which do not have gears
}



public class CarAdapter implements Car {

    @Override
    public void drive(int Speed, int Gear) {
        // TODO Auto-generated method stub

    }

    @Override
    public void drive(int Speed) {
        // TODO Auto-generated method stub

    }

}


public class AdvancedCar extends CarAdapter {

    @Override
    public void drive(int Speed) {
        // TODO Auto-generated method stub
        super.drive(Speed);
    }

    @Override
    public void drive(int Speed, int Gear) {
        // TODO Auto-generated method stub
        super.drive(Speed, Gear);
    }

}


public class SimpleCar extends CarAdapter {

    @Override
    public void drive(int Speed) {
        // TODO Auto-generated method stub
        super.drive(Speed);
    }


}